Might have a idea for it..... Straight from MicroSofts mouth. I hope you follow up on this and report it to Microsoft and get detailed instructions on removal of the Malware thats cuasing this.

Could be any number of them, depending on what the MS team analysis find.

Acpi.sys is a Windows driver. A driver is a small software program that allows your computer to communicate with hardware or connected devices. This means that a driver has direct access to the internals of the operating system, hardware etc. The original acpi.sys is an important part of Windows and rarely causes problems. Acpi.sys is located in the C:\Windows\System32\drivers folder.

Note:Some malware disguises itself as acpi.sys, particularly when not located in the C:\Windows\System32\drivers folder. Therefore, you should check the acpi.sys process on your PC to see if it is a threat. We recommend to run the Microsoft safety scanner and to verify the security related issues.

The Microsoft Safety Scanner is a free downloadable security tool that provides on-demand scanning and helps remove viruses, spyware, and other malicious software. It works with your existing antivirus software.

Try to download the Microsoft Safety Scanner and check if it helps.